Provide actual bounds to Shader primitives

... and allow for proper translation and scissoring.

examples/custom_shader/src/main.rs

@@ -5,9 +5,7 @@ use scene::Scene;
 use iced::executor;
 use iced::time::Instant;
 use iced::widget::shader::wgpu;
-use iced::widget::{
-    checkbox, column, container, row, shader, slider, text, vertical_space,
-};
+use iced::widget::{checkbox, column, container, row, shader, slider, text};
 use iced::window;
 use iced::{
     Alignment, Application, Color, Command, Element, Length, Renderer,
@@ -138,21 +136,18 @@ impl Application for IcedCubes {
 
         let controls = column![top_controls, bottom_controls,]
             .spacing(10)
+            .padding(20)
             .align_items(Alignment::Center);
 
         let shader =
             shader(&self.scene).width(Length::Fill).height(Length::Fill);
 
-        container(
-            column![shader, controls, vertical_space(20),]
-                .spacing(40)
-                .align_items(Alignment::Center),
-        )
-        .width(Length::Fill)
-        .height(Length::Fill)
-        .center_x()
-        .center_y()
-        .into()
+        container(column![shader, controls].align_items(Alignment::Center))
+            .width(Length::Fill)
+            .height(Length::Fill)
+            .center_x()
+            .center_y()
+            .into()
     }
 
     fn subscription(&self) -> Subscription<Self::Message> {

examples/custom_shader/src/scene.rs

@@ -133,9 +133,9 @@ impl shader::Primitive for Primitive {
         format: wgpu::TextureFormat,
         device: &wgpu::Device,
         queue: &wgpu::Queue,
+        _bounds: Rectangle,
         target_size: Size<u32>,
         _scale_factor: f32,
-        _transform: shader::Transformation,
         storage: &mut shader::Storage,
     ) {
         if !storage.has::<Pipeline>() {
@@ -158,9 +158,9 @@ impl shader::Primitive for Primitive {
     fn render(
         &self,
         storage: &shader::Storage,
-        bounds: Rectangle<u32>,
         target: &wgpu::TextureView,
         _target_size: Size<u32>,
+        viewport: Rectangle<u32>,
         encoder: &mut wgpu::CommandEncoder,
     ) {
         //at this point our pipeline should always be initialized
@@ -170,7 +170,7 @@ impl shader::Primitive for Primitive {
         pipeline.render(
             target,
             encoder,
-            bounds,
+            viewport,
             self.cubes.len() as u32,
             self.show_depth_buffer,
         );

examples/custom_shader/src/scene/pipeline.rs

@@ -351,7 +351,7 @@ impl Pipeline {
         &self,
         target: &wgpu::TextureView,
         encoder: &mut wgpu::CommandEncoder,
-        bounds: Rectangle<u32>,
+        viewport: Rectangle<u32>,
         num_cubes: u32,
         show_depth: bool,
     ) {
@@ -384,10 +384,10 @@ impl Pipeline {
                 });
 
             pass.set_scissor_rect(
-                bounds.x,
-                bounds.y,
-                bounds.width,
-                bounds.height,
+                viewport.x,
+                viewport.y,
+                viewport.width,
+                viewport.height,
             );
             pass.set_pipeline(&self.pipeline);
             pass.set_bind_group(0, &self.uniform_bind_group, &[]);
@@ -397,7 +397,7 @@ impl Pipeline {
         }
 
         if show_depth {
-            self.depth_pipeline.render(encoder, target, bounds);
+            self.depth_pipeline.render(encoder, target, viewport);
         }
     }
 }
@@ -550,7 +550,7 @@ impl DepthPipeline {
         &self,
         encoder: &mut wgpu::CommandEncoder,
         target: &wgpu::TextureView,
-        bounds: Rectangle<u32>,
+        viewport: Rectangle<u32>,
     ) {
         let mut pass = encoder.begin_render_pass(&wgpu::RenderPassDescriptor {
             label: Some("cubes.pipeline.depth_pass"),
@@ -573,7 +573,12 @@ impl DepthPipeline {
             occlusion_query_set: None,
         });
 
-        pass.set_scissor_rect(bounds.x, bounds.y, bounds.width, bounds.height);
+        pass.set_scissor_rect(
+            viewport.x,
+            viewport.y,
+            viewport.width,
+            viewport.height,
+        );
         pass.set_pipeline(&self.pipeline);
         pass.set_bind_group(0, &self.bind_group, &[]);
         pass.draw(0..6, 0..1);